Organisms that are harmful to trees that proliferate from spring through fall eat into the leaves, branches or tree body, and may impair tree growth or occasionally cause the tree to die. In addition, there are also a considerable number of harmful insects that are harmful to people, and damage is prevented or harmful insects are eradicated using various methods.
Although the method of spraying chemicals has primarily been employed in the past to prevent damage to trees by harmful organisms, in the case of scenic trees planted in parks, schools or residential areas, since this spraying has the risk of having an effect on the living environment of surrounding residents or causing chemical damage to the paint of automobiles and buildings, various restrictions have been placed on spraying.
In order to overcome these restrictions, trunk injection preparations have conventionally been used, in the case of pine trees in particular. Trunk injection preparations currently in use are targeted at pine wood nematodes, and prevent the death of pine trees by dispersing a chemical inside the tree body and eradicating pine wood nematodes that infiltrated therein. Although these active ingredients have insecticidal activity against pine wood nematodes, they are not recognized to have insecticidal effects on the Japanese pine sawyer that damages pine tree branches using pine wood nematodes as a medium.
In addition, in the case where the aqueous solubility of the active ingredient is low, proposals have been made to improve dispersivity of a chemical inside the tree body by preparing a solubilizing preparation containing a surfactant (Japanese Patent Laid-Open Publication No. Hei 8-175914). However, damage in the form of leaf discoloration and leaf fall occur in the case of injecting existing trunk injection preparations into trees other than pine trees using these technologies.
In addition, a chemical is used for cherry trees in which an organic phosphorus-based insecticide known as acephate filled into a water-soluble capsule is contained in a cartridge and then pounded into a tree trunk using a hammer and so forth to eradicate leaf-eating insects such as the fall webworm and cherry caterpillar. Since this chemical is pounded into a tree body after filling only the active ingredient into a capsule, it is thought to have problems with stability of the effects in consideration of the dispersivity of the chemical inside the tree body. In addition, since a cartridge must be pounded in for each 10 cm of the trunk circumference, and the cartridge remains inside the tree trunk, it also has the problem of placing a considerable burden on the tree.
The object of the present invention is to provide a composition that prevents damage to trees with only a small amount that solves the problems of trunk injection preparations currently in use by demonstrating efficacy on numerous types of trees and numerous harmful insects, causing no chemical damage, and containing an active ingredient that has a higher degree of insecticidal activity than organic phosphorus-based chemicals and other existing active ingredients.
As a result of extensive researches into solving these problems, the inventors of the present invention found that the blending of a neonicotinoid-based insecticide component demonstrates efficacy even in small amounts on harmful insects of numerous types of trees.
Neonicotinoid-based compounds per se are known, and thiamethoxam, for example, is used as an agricultural insecticide. However, the injection of these compounds into the trunk of a tree for the purpose of preventing damage to numerous types of trees by harmful insects has never been reported.
On the other hand, since there are some neonicotinoid-based compounds that have low solubility in water, they have poor dispersivity within a tree body even if injected into the tree body after dissolving in an organic solvent, resulting in the occurrence of problems with eradication effects on harmful insects.
In the composition of the present invention, the type and amount of surfactant are selected and adjusted to prevent damage to numerous types of trees by improving solubility in water of nicotinoid-based compounds inherently having a low level of aqueous solubility to facilitate dispersion of the compound within the tree body and demonstrate stable eradication effects.
Namely, the present invention is a method for preventing damage to trees by injecting into a tree a composition containing an insecticide or bactericide active ingredient, surfactant for which the type and amount are limited, water and/or an organic solvent, and dispersing that composition within the tree body to prevent and eradicate various harmful insects while causing no chemical damage.
There are no particular restrictions on the type of tree, and examples include not only mountain trees such as pine, cedar and cypress, but also fruit trees such as citrus, apple, pear, fig, persimmon, peach, grape, chestnut, cherry, plum, prune, loquat, oleaster and apricot trees, flowering trees such as lilac, sasanqua, camellia, althea and cherry trees, and yard trees such as oak, gardenia, devilwood and maple trees.
Examples of harmful insects include infestation insects such as gold beetles, leaf folders, caterpillars, sawflys and miters, sap-sucking insects such as aphids, coccids, and Ceroplastes rubens, hole-boring insects such as long-horned beetles, wood borers, weevils and lesser grain borers, harmful insects that cause damage by growing inside trees such as nematodes, harmful insects such as spider mites, and harmful insects that cause diseases such as mildew, black spot disease, black star disease, red star disease, rust disease, white spot disease, round spot disease, soot disease, root rot and swollen leaf disease.
Examples of insecticide or bactericide active ingredients that are effective in controlling these harmful insects include neonicotinoid-based insecticides such as thiamethoxam, acetamiprid, clotianidin, dinotefuran, thiacloprid, and imidacloprid, acaricides such as pyrimidifen, tebufenpyrad and chlorphenapyr, macrolide-based nematode-controlling agents and acaricides such as avermectin, milvemectin and nemadectin, ergosterol biosynthesis-inhibiting antimicrobials such as triflumizole, bitertanol and fenarimol, dithiocarbamate-based antimicrobials such as thiuram, zineb and mancozeb, carbendazim-producing antimicrobials such as benomyl and zetophencarb, and antibiotics such as kasugamycin, polyoxine and streptomycin. These insecticide or bactericide active ingredients may be used alone or as a combination of two or more types.
Since many of these active ingredients are hardly soluble in water, simply dissolving the active ingredient in an organic solvent does not allow the obtaining stable effects in nearly all cases due to poor dispersion within the tree body as a result of the active ingredient not being dissolved in the flow of sap through the trunk. Consequently, the use of a surfactant is an effective means for dissolving the active ingredient in the trunk flow. There are no particular restrictions on the surfactant used, and a nonionic, anionic or cationic surfactant may be used.
Examples of anionic surfactants used in the composition of the present invention include alkyl sulfate esters, alkane sulfonates, alkyl benzene sulfonates, alkyl phosphate esters, N-acyl sarcosine salts, N-acyl alanine salts and succinates, cationic surfactants such as alkyl amines, alkyl trimethyl ammonium salts, dialkyl dimethyl ammonium salts, alkyl dimethyl benzyl ammonium salts and alkyl pyridinium salts, and nonionic surfactants such as polyoxyethylene castor oils, polyoxyethylene hardened castor oils, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl phenyl ether formaldehyde condensation products, polyoxyethylene allyl phenyl ethers, polyoxyethylene allyl phenyl ether formaldehyde condensation products, polyethylene glycol fatty acid esters, polyoxyalkylene alkyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyglycerin fatty acid esters, sucrose fatty acid esters and propylene glycol mono fatty acid esters.
Among these, a suitable nonionic surfactant is normally used alone or as a mixture with an anionic surfactant. In addition, since there are cases where chemical damage may be caused according to the type of tree depending on the type and blended amount of surfactant, it is necessary to suitably adjust the surfactant according to the target tree type. Preferable examples of nonionic surfactants particularly include polyoxyethylene hardened castor oils, polyoxyethylene alkyl ethers, polyoxyalkylene alkyl ethers, polyoxyethylene allyl phenyl ethers and polyoxyethylene sorbitan fatty acid esters.
The solvent used in the composition of the present invention is preferably that which is easily miscible with water, examples of which include lower alcohols such as methanol and ethanol, ethers such as dioxane and tetrahydrofuran, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, sulfoxides such as dimethyl sulfoxide, nitriles such as acetonitrile, pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone, amides such as N,N-dimethylformamide, and glycols such as ethylene glycol, propylene glycol and diethylene glycol, their esters and their ethers.
Since the composition may not be injected into the tree body if the viscosity is excessively high, normally a solvent having low viscosity is preferable. In addition, since these organic solvents may also cause chemical damage according to the type of tree depending on the type and blended amount in the same manner as surfactant, it is necessary to suitably adjust the solvent according to the target tree type.
Fertilizer components and trace elements and so forth that have the action of activating trees and plants can also be blended into the composition of the present invention as other components. The injection of these components into a tree body after blending into the composition is an effective method for activating trees that have been emaciated by insect damage. In addition to the three major fertilizer elements of nitrogen, phosphorus and potash, these components also include trace elements such as calcium, sulfur, zinc, copper, molybdenum, boron, iron, manganese, magnesium and various vitamins.
Although the amount of each component of the composition of the present invention may be suitably altered, an active ingredient can be contained at about 0.1 to 20% and preferably about 1 to 10%, a surfactant at about 0 to 20% and preferably about 0 to 10%, and an organic solvent at about 30-80% and preferably about 40 to 70%.
The composition of the present invention is prepared by uniformly dissolving each of these components. The preparation method consists of mixing and dissolving the entire amount using a mixer in a tank of a suitable size.
The method for applying the present composition to trees consists of drilling a hole in the tree trunk, and injecting the composition of the present invention contained in a suitable container either without applying pressure or under pressure. The amount applied is suitably adjusted according to the size of the tree, target harmful insect, degree of damage and so forth.
Although the following provides a detailed explanation of the contents of the present invention through its examples, the present invention is not limited to these examples.